A lumbar laminectomy is a complex and delicate operation, with the possibility of complications such as excessive hemorrhage from the epidural veins, life-threatening injuries to retroperitoneal major blood vessels and tearing of spinal nerves or the dura.
Previous operating procedures for spinal operations called for placing the patient face-down in a horizontal position on a flat surgical table top. In this position, the patient greatest weight is supported primarily by the abdomen on the flat table top. Furthermore, the knees are straight, and the legs extended. However, this has created two problems with which the spinal surgeon has had to contend, and which have an adverse, complicating effect on the surgical procedure. The first problem was that with the patient in the aforesaid position, it was difficult to control and minimize blood loss. As is well known, excessive loss of blood during an operation poses an immediate risk of harm to the patient, due to either the loss of blood itself, or the risk of hepatitis infection concomitant with any blood transfusion. Excessive bleeding at the operation site also obscures the operating field hindering the ability of the surgeon to see his work clearly.
Blood loss during a spinal surgical operation is a function of the degree of intraspinal venous engorgement. That is, whether the blood vessels in the spinal area are full and under pressure, or drained. If the patient is positioned face down on the operating table, as was the standard operating procedure in the prior art, the abdominal area supports a large portion of the patient's weight. This, in turn, causes the viscera to be forced against the spinal column which results in intraspinal engorgement as the blood in the spinal area is retained there and the blood in the visceral area is forced into the spinal area.
Moreover, when the patient is lying face down on the surgical table with his knees straight and his legs extended, the spinal column is under a compressive load. For any operation on the spine, the surgeon prefers to have the spine in a flexed position, that is, in a relaxed state under no load.
Accordingly, it is important for a lumbar laminectomy that the patient be placed with the hips flexed at a right-angle in order to open up the back of the spine and allow for the surgical procedure with a minimum removal of bone from the laminar area. The patient's knees should be flexed to a 90.degree. angle, and the weight of the patient is preferably supported by the iliac crests (hips) and also by the lower portion of the chest. This removes the pressure from the abdomen and decreases bleeding in th spine during the surgical procedure due to the decreased intra-abdominal pressure.
Because of the foregoing, various attachments have been proposed to surgical tables, so that the patient may be placed in a more appropriate position for a spinal operation. Such attachments are described, for example, in Cloward U.S. Pat. No. 4,398,707 and in Wayne U.S. Pat. No. 4,444,381. However, such attachments are subject to certain disadvantages. In some instances, the patient is held, for example, in an upright fetal position with the knees pulled forward to the chest. Although this does flex the spine, the patient is placed in a most uncomfortable position and free breathing is restrictive. Also, the viscera is forced against the spinal column so that blood loss is accelerated.
In all cases, where such attachments are used in conjunction with a regular operating table, up to an hour of valuable surgical time is lost in placing the patient in proper position on the table. An objective of the present invention is to provide an operating table which is particularly constructed for lumbar laminectomy surgery, and which enables the patient to be placed in the proper position in a matter of minutes.
The operating table of the present invention is constructed to achieve the criteria set forth in the preceding paragraph. The operating table of the invention is a special lumbar surgical table which permits the patient to be positioned in the proper hip and knee 90/90 position in a matter of minutes. This position opens the posterior interlaminal area and minimizes the need for bone dissection of the lamina. The lack of pressure on the abdomen also minimizes bleeding from Batson's vein around the dura. The patient is suspended by the iliac crests and the xyphoid. The patient's head is closer to the anesthesiologist and provides for better monitoring during surgery. There is no pressure nor any acute flexion of the knees so that the venous system is not compromised and there is less danger of a post-operative thrombophlebitis.
In addition, the table of the invention is constructed to permit the C-arm of a standard X-ray machine to be inserted through one side of the table to be directly under and over the patient so as to permit anterior/posterior (AP) as well as lateral X-ray to be taken. In this way, exact coordinates may be provided to the surgeon of the location of the area of the body to which the surgical procedure is to be directed.
A special surgical microscope is attached directly to the table, and this obviates the necessity to move in the large surgical microscope so as to save valuable operating time and space. The patient is placed on the table, and the microscope is then rotated around to the desired position. With proper positioning of the patient, and with the placement of the surgical microscope and the special instruments, the surgical procedure utilizing the table of the present invention can be performed in about half an hour, as compared with two or three hours required for the usual lumbar laminectomy using the prior art equipment.